The present invention relates to surgical cutting instruments and more particularly to surgical cutting instruments used in ophthalmic surgery. It further relates to surgical cutting instruments for use in cutting and evacuating material from parts and organs of animal and human bodies. It also pertains to vitrectomy handpieces for providing irrigating and aspirating and cutting functions for cutting and removing vitreous, blood clots and other material from the eye during intraocular surgery, and to such handpieces which more particularly incorporate reciprocating cutters.
Many surgical instruments have been designed in the recent past to said ophthalmic surgeons in removing vitreous, blood clots, cataracts, lenses and other matter from the eye. These instruments typically have an elongated probe defining a cutter at the distal end thereof, which is inserted into the body, for example into the eye through an incision in the cornea or sclera. The probe thereof is typically formed by coaxial inner and outer tubes wherein a port is provided in the outer tube adjacent the end and the inner tube moves relative thereto, and the inner and outer tubes cut the material as it is drawn in through the port. The excised tissue is aspirated by suction from the interior of the body part, such as the eye, possibly together with fluid, through the central lumen of the hollow inner tube, and is collected in a collection vessel.
It has been found that when the inner tube motion is rotational relative to the outer tube that the vitreous and other materials are pulled or sheared while being cut. Thus, the current practice is to provide for the inner tube to reciprocate longitudinally relative to the outer tube and thereby provide a chopping or guillotine type of action to cleanly cut the vitreous body. Many methods are known for effecting this reciprocating movement of the inner cylinder including utilizing an electric motor or a pneumatic actuator positioned in the handpiece, and these include the devices disclosed in U.S. Pat. No. 4,246,902, to Martinez, and U.S. Pat. No. 4,674,502, the entire contents of both of which are hereby incorporated by reference. It is also known to use a bellows positioned in the handpiece with the inner cutting tube being secured to the bellows, and a means for alternately supplying compressed air and vacuum to the bellows. This arrangement is shown for example in U.S. Pat. No. 3,884,238, whose entire contents are also hereby incorporated by reference. It is further known to include on the surgical cutting tool an infusion sleeve or similar means for providing irrigation either during or separately from the cutting procedure. This irrigation means can bathe the surgical site in a physiological fluid and for ophthalmic surgery can maintain the intraocular pressure to prevent the collapse of the eyeball.
These known cutting instruments though suffer from many disadvantages, including the difficulty in assembling them, excessive vibrations created by the handpiece, inability to attain cutting speeds greater than 600 cuts per minute, lack of suitable means for adjusting the size of the cutting and aspirating port, and the presence of outside moving parts on the handpiece. Thus, a need has arisen for an improved design for such surgical cutting instruments.
Accordingly, it is a principal object of the present invention to provide an improved design for a surgical cutting instrument.
Another object of the present invention is to provide an improved surgical cutting instrument construction which can be easily assembled and is designed to be economically disposable after a single use.
A further object of the present invention is to provide an improved construction of a surgical cutting instrument having an infusion component which can be easily adjusted.
A still further object of the present invention is to provide an improved surgical cutting instrument design which reduces the vibrations created by the handpiece thereof.
Another object is to provide an improved vitrectomy handpiece having no moving parts outside of the body of the handpiece.
A further object is to provide an improved surgical cutting instrument having greater cutting speeds for increased efficiency and safety.
Other objects and advantages of the present invention will become apparent to those persons of ordinary skill in the art from the foregoing description taken in conjunction with the accompanying drawings.